1. Field of the Invention
The present invention relates to polymers containing borate groups, alkynyl groups, at least one silyl group and/or at least one siloxyl group.
2. Description of the Related Technology
Thermally stable polymeric elastomers consisting of alternating carborane and siloxane groups are known for both the deca- and penta-carboranes (HCB10H10CH and HCB5H5CH respectively). See, for example, U.S. Pat. No. 3,463,801. Some have been produced commercially. However, these materials do not contain alkynyl moieties such as acetylenic groups or any other functional group for crosslinking to produce thermosetting polymers. These poly(carborane-siloxane) elastomers show superior thermal (high chars) and oxidative properties (low weight loss) at elevated temperatures (900xc2x0 C.) as compared to analogous poly(siloxanes) as monitored by thermogravimetric analysis (TGA).
Silylene or siloxane-acetylene and silylene or siloxane-diacetylene polymers have also been reported. See, for example, U.S. Pat. No. 5,483,017. Good quality fibers can be drawn from the melts of the silylene polymers either thermally or with UV light, but they lack the thermally and oxidatively stable boron-containing units.
Linear inorganic-organic polymers containing acetylenic and either bis(silyl or siloxyl)carboranyl units or a random distribution of both bis(silyl or siloxyl)carboranyl and bis(silyl or siloxy) units have also been described. See, for example, U.S. Pat. No. 5,272,237. However, these polymers contain carborane units in each repeating unit which result in a limited availability and high cost.
Accordingly, it is an objective of certain embodiments of the present invention to provide a polymer having improved thermal stability by incorporating boron into its backbone.
It is another objective of certain embodiments of the present invention to provide a cross-linkable boron-containing polymer.
It is another objective of certain embodiments of the present invention to provide a low cost boron-containing polymer useful for making high-temperature, oxidatively stable thermosets or ceramics.
In a first aspect, the present invention provides a polymer produced by reacting a first compound having at least one alkynyl group, at least one silyl group and/or at least one siloxyl group with a second compound selected from boric acid, hydrocarbon boronic acid, hydrocarbon borate, boron oxide, and pyroboric acid.
In a second aspect, the present invention provides a method of preparing an organoboron polymer including the step of reacting a first compound having at least one alkynyl group, at least one silyl group and/or at least one siloxyl group with a second compound selected from boric acid, hydrocarbon boronic acid, hydrocarbon borate, boron oxide, and pyroboric acid.
In a third aspect, the present,invention provides a polymer having a repeating unit including, at least one alkynyl group, at least one borate group, at least one silyl group and/or at least one siloxyl group.